As computing devices continue to become more ubiquitous, they are also becoming smaller. In many cases, handheld computing devices execute telephony applications, data communication applications, a calendar application and a contact management application. As such, it is desirable to have the handheld computing devices available quickly. To this end, rather than keep a handheld computing device in a purse or briefcase, many people opt for a holster to allow the handheld computing device to be attached to a belt around the waist of the user or attached to the outside of a bag.
Typical components of a handheld computing device include an output device, such as a display screen, an input device, such as a keypad, and a battery, to allow operation away from fixed power sources. It has been recognized that providing power to the display screen is one of the activities that drains the battery most quickly. As such, many handheld computing devices have been designed to sense the suspension of user activity on the handheld computing device. For example, a handheld computing device may sense the presence of a corresponding holster and, responsive to sensing the close proximity of the holster, enter into a user-inactive mode. Entering the user-inactive mode may be defined to include disabling the display screen. In one example, the holster is provided with a magnet. The corresponding handheld computing device is provided with a Hall Effect sensor in a position that corresponds, when the handheld computing device is in the holster, to the location of the magnet in the holster. When the handheld computing device is placed in the holster, the magnet is sensed by the Hall Effect sensor and the handheld computing device enters into the user-inactive mode.
As well as disabling the output device responsive to sensing close proximity of the holster, entering into the user-inactive mode may also involve disabling the input device, as it is unlikely that the user will be providing input while the handheld computing device is in the holster. However, often presses of keys on the keypad are recorded as the handheld computing device is going into, and coming out of, the holster. That is, unintended input is received by the handheld computing device while the handheld computing device is too far from the magnet to sense the magnet and, responsively, enter into the user-inactive mode.
Clearly it would be advantageous to enter into the user-inactive mode, and, thus, disable input devices, before unintentional input occurs. Furthermore, additional power savings may be realized by disabling output devices earlier than is done in present practice.